Secretory processes for electrolytes and proteins is a continuing objective of this work. The salivary glands of adult and immature, and the microperfused main duct of SM control of neural (autonomic nervous system) factors. The investigation of growth regulation in early postnatal rats by dietary, chemical and surgical manipulations are expected in delineate changes in glandular physiology and biochemistry associated with the time of weaning. The postnatal development of electrolyte and protein secretory ability of SM and PA glands as well as the concurrent development of their neural elements (especially autonomic receptors) will be investigated by electrophysiological, histochemical (catecholamine fluorescence) and biochemical (endogenous norepinephrine and choline acetyltransferase activity) methods; histologic changes at the light and EM levels that accompany secretory and neural development will also be assessed. In adult and immature rat, the functional status of glands modified in size by dietary or surgical manipulations will be evaluated by their ability to secrete electrolytes and protein in response to autonomic stimulation. The concourrent changes in the nerve activity or number of and affinity of autonomic receptor binding sites or levels of cyclic nucleotides will be also determined in "atrophied" and enlarged glands of adult or immature rats. In the immature, manipulations leading to enlargement or atrophy of glands is also expected to lead to premature or retarded maturation of neural elements and secretory activity. Secretion of amylase and calcium by SM and PA will be an important aspect of this work since calcium is known to exert an important role in many biological processes including stimulus-secretion coupling and ion transport. Further clarification of autonomic control of salivary secretion is important for understanding of pathophysiology of cystic fibrosis. In addition, delineation of ductal secretory and reabsorptive processes of ions and their autonomic regulation is essential to an understanding of the steps by which saliva is formed and secreted.